Heliograph, c1900. The Heliograph, a visual telegraph for sending and receiving messages by means of mirrors and sunlight. Here a British signal unit in tropical kit is flashing a message to the fort in the distance. Trade card for Liebig Meat Extract. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Heritage Images / Ann Ronan Picture Library |
Bildgröße: | 5096 px × 3429 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |